Self-Sealing Coating for Fuel Tanks

ABSTRACT

A method of forming a self-sealing fuel tank includes: providing a container including internal surfaces and external surfaces and configured to hold a fuel; forming a latex coating layer over at least a portion of the internal surfaces and/or external surfaces; depositing or encapsulating an environmental layer over at least a portion of the latex coating layer; where the latex coating layer swells when contacted with the fuel; and where the latex coating layer is formed from a latex coating composition that is substantially free of a non-ionic associative thickener.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 63/185,437, filed May 7, 2021, the disclosure of whichis hereby incorporate by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure is generally directed to a fuel tank and methodsof forming a fuel tank system and, in particular, to a self-sealingcoating for fuel tanks.

Technical Considerations

In certain vehicles, fuel tanks are provided in order to contain thefuel used to power said vehicles. The fuel tank is typically mountedonto the frame of the vehicle and is connected to the engine in order tocontinuously provide fuel for operation of the vehicle. The fuel tankwill contain the fuel for the vehicle until such time that said fuel isneeded to power the vehicle, where at such point a portion of the fuelwill be ushered to the engine. These fuel tanks may be used in a numberof different applications including military vehicles, commercialvehicles, large/heavy vehicles, secondary fuel transportation devicesand vehicles, and the like.

Typically, the fuel contained by the fuel tank is a combustiblecompound, such as gasoline, diesel, and/or another petroleum-basedcompound. During the lifetime of the fuel tank, said fuel tank may besubject to weathering due to atmospheric exposure (e.g., oxidation), ormay even be punctured, such as by munition or an obstruction present inthe road or path. Due to the fuel tank being punctured and/orcompromised, the fuel contained within may leak out. This leak of fuelis dangerous to the further operation of the vehicle because the fuelleaking from the fuel tank may be ignited; causing a fire and/orexplosion that puts any person in proximity in danger.

Currently, sheets of swellable material may be used to prevent leakageof fuel from the fuel tank. The swellable material of these sheets maybe a material that swells when exposed to a fuel. Referring to FIG. 1,sheets of swellable material 2 may be cut to the shape of the fuel tankcontainer 1 and secured to the external surfaces 3 of the container 1.However, due to the complex geometry of fuel tanks, it is difficult tocut the sheets of swellable material 2 to cover the external surfaces 3of the container 1, leading to a lesser protected external surfaces 3and the possibility of fuel leaking out without being sealed by theswellable material. Further, the measuring and cutting of each sheet ofswellable material 2 is excessively time consuming, resulting in aproduction time for a fuel tank comprising said sheets of swellablematerial 2 of over a week. Similar difficulties are observed when tryingto cover the internal surfaces of the container 1 with the sheets ofswellable material.

SUMMARY OF INVENTION

In view of the foregoing, there is a current need for a coatingcomposition that may be applied onto a fuel tank and that swells whenexposed to a fuel to seal one or more holes that become immediatelypresent in the fuel tank due to the effect of munitions, which may bereferred to herein as a self-sealing fuel tank. Further, there is acurrent need in the art for a method of forming a self-sealing fueltank. In addition, there is a current need in the art for a method ofsealing one or more holes in a fuel tank comprising a fuel.

In one aspect of the present invention, a method of forming aself-sealing fuel tank includes: providing a container includinginternal surfaces and external surfaces and configured to hold a fuel;forming a latex coating layer over at least a portion of the internalsurfaces and/or external surfaces; depositing or encapsulating anenvironmental layer over at least a portion of the latex coating layer;where the latex coating layer swells when contacted with the fuel; andwhere the latex coating layer is formed from a latex coating compositionthat is substantially free of a non-ionic associative thickener.

In another aspect of the present invention, a self-sealing fuel tankincludes: a container including internal surfaces and external surfacesand configured to hold a fuel; a latex coating layer over at least aportion of the internal surfaces and/or external surfaces; and anenvironmental layer over at least a portion of the latex coating layer;where the latex coating layer swells when contacted with the fuel; andwhere the latex coating layer is formed from a latex coating compositionthat is substantially free of a non-ionic associative thickener.

In another aspect of the present invention, a method of sealing one ormore punctures in the wall of a container includes: forming a latexcoating layer over at least a portion of the internal surfaces and/orexternal surfaces; where the container comprises a fuel which contactsthe latex coating layer at one or more surfaces exposed by the one ormore punctures; where said contact between the fuel and the latexcoating layer causes the latex coating layer to swell and seal the oneor more punctures; and where the latex coating layer is formed from alatex coating composition that is substantially free of a non-ionicassociative thickener.

The present invention is also disclosed according to the followingclauses:

Clause 1: A method of forming a self-sealing fuel tank, comprising:providing a container comprising internal surfaces and external surfacesand configured to hold a fuel; forming a latex coating layer over atleast a portion of the internal surfaces and/or external surfaces; anddepositing or encapsulating an environmental layer over at least aportion of the latex coating layer; wherein the latex coating layerswells when contacted with the fuel; and wherein the latex coating layeris formed from a latex coating composition that is substantially free ofa non-ionic associative thickener.

Clause 2: The method of clause 1, wherein the forming step furthercomprises applying the latex coating composition onto at least a portionof the internal surfaces and/or the external surfaces, and curing thelatex coating composition to form the latex coating layer.

Clause 3: The method of clause 1, wherein the forming step furthercomprises molding and curing the latex coating composition intopreformed layers, and affixing the preformed layers over at least aportion of the internal surfaces and/or external surfaces.

Clause 4: The method of any of clauses 1-3, further comprisingdepositing an adhesion promoter over at least a portion of the internalsurfaces and/or external surfaces prior to forming the latex coatinglayer.

Clause 5: The method of clause 2, wherein the applying step comprisesspraying, casting, brushing, rolling, and/or dipping the latex coatingcomposition onto at least a portion of the external surfaces of thecontainer.

Clause 6: The method of clause 2, wherein the applying step comprisesspraying, casting, brushing, rolling, and/or dipping the latex coatingcomposition onto at least a portion of the internal surfaces of thecontainer.

Clause 7: The method of any of clauses 1-6, wherein the depositing orencapsulating step further comprises spraying and/or casting anenvironmental coating composition over at least a portion of the latexcoating layer and curing the environmental coating composition to formthe environmental layer, or molding and curing the environmental coatingcomposition into preformed layers and affixing the preformed layers overat least a portion of the latex coating layer.

Clause 8: The method of any of clauses 1-7, further comprisingcompounding at least one latex polymer, an ionic gelling agent, and afoaming agent to form the latex coating composition.

Clause 9: The method of any of clauses 1-8, wherein the curing stepcomprises heating the latex coating composition to a temperature in therange of 60° C. to 95° C.

Clause 10: The method of any of clauses 1-9, wherein the latex coatingcomposition is a one-component coating composition.

Clause 11: The method of any of clauses 1-10, wherein the latex coatinglayer has a density in a range of from 0.09 g/cc to 0.50 g/cc.

Clause 12: The method of any of clauses 1-11, wherein the latex coatinglayer has a tensile strength in a range of from 20 psi to 200 psi.

Clause 13: The method of any of clauses 1-12, wherein the environmentallayer is in direct contact with the latex coating layer.

Clause 14: The method of any of clauses 1-12, further comprisingproviding a barrier and/or strengthening layer over at least a portionof the latex coating layer, and depositing or encapsulating theenvironmental layer over at least a portion of the barrier and/orstrengthening layer.

Clause 15: A self-sealing fuel tank, comprising: a container comprisinginternal surfaces and external surfaces and configured to hold a fuel; alatex coating layer over at least a portion of the internal surfacesand/or external surfaces; and an environmental layer over at least aportion of the latex coating layer; wherein the latex coating layerswells when contacted with the fuel; and wherein the latex coating layeris formed from a latex coating composition that is substantially free ofa non-ionic associative thickener.

Clause 16: The self-sealing fuel tank of clause 15, further comprisingan adhesion promoter over at least a portion of the internal surfacesand/or external surfaces and in between the portion of the internalsurfaces and/or external surfaces and the latex coating layer.

Clause 17: The self-sealing fuel tank of clause 15 or clause 16, whereinthe latex coating layer is over at least a portion of the internalsurfaces.

Clause 18: The self-sealing fuel tank of any of clauses 15-17, whereinthe latex coating layer is over at least a portion of the externalsurfaces.

Clause 19: The self-sealing fuel tank of any of clauses 15-18, whereinthe container comprises a metal, a plastic, and/or a rubber.

Clause 20: The self-sealing fuel tank of any of clauses 15-19, whereinthe latex coating composition comprises at least one latex polymer.

Clause 21: The self-sealing fuel tank of clause 20, wherein the latexcoating composition further comprises an ionic gelling agent.

Clause 22: The self-sealing fuel tank of clause 20 or clause 21, whereinthe latex coating composition further comprises a foaming agent.

Clause 23: The self-sealing fuel tank of any of clauses 20-22, whereinthe latex coating composition further comprises a colorant.

Clause 24: The self-sealing fuel tank of any of clauses 20-23, whereinthe latex coating composition further comprises a thickening agent.

Clause 25: The self-sealing fuel tank of any of clauses 15-24, whereinthe latex coating composition is sprayed, casted, brushed, rolled,and/or dipped onto at least a portion of the internal surfaces and/orthe external surfaces.

Clause 26: The self-sealing fuel tank of any of clauses 15-24, whereinthe latex coating composition is molded and cured into preformed layers,and the preformed layers are affixed to at least a portion of theinternal surfaces and/or external surfaces.

Clause 27: The self-sealing fuel tank of any of clauses 15-26, whereinthe latex coating composition is a one-component coating composition.

Clause 28: The self-sealing fuel tank of any of clauses 15-27, whereinthe latex coating layer has a density in a range of from 0.09 g/cc to0.50 g/cc

Clause 29: The self-sealing fuel tank of any of clauses 15-28, whereinthe latex coating layer has a tensile strength in a range of from 20 psito 200 psi.

Clause 30: The self-sealing fuel tank of any of clauses 15-29, whereinthe environmental layer is in direct contact with the latex coatinglayer.

Clause 31: The self-sealing fuel tank of any of clauses 15-29, furthercomprising a barrier and/or strengthening layer over at least a portionof the latex coating layer, and the environmental layer over at least aportion of the barrier and/or strengthening layer.

Clause 32: A method of sealing one or more punctures in the wall of acontainer, comprising: forming a latex coating layer over at least aportion of the internal surfaces and/or external surfaces; wherein thecontainer comprises a fuel which contacts the latex coating layer at oneor more surfaces exposed by the one or more punctures; wherein saidcontact between the fuel and the latex coating layer causes the latexcoating layer to swell and seal the one or more punctures; and whereinthe latex coating layer is formed from a latex coating composition thatis substantially free of a non-ionic associative thickener.

Clause 33: The method of clause 32, wherein the forming step furthercomprises applying the latex coating composition onto at least a portionof the internal surfaces and/or external surfaces, and curing the latexcoating composition to form the latex coating layer.

Clause 34: The method of clause 32, wherein the forming step furthercomprises molding and curing the latex coating composition intopreformed layers, and affixing the preformed layers over at least aportion of the internal surfaces and/or external surfaces.

Clause 35: The method of any of clauses 32-34, wherein the latex coatinglayer comprises septum properties such that at least one of the one ormore punctures is mechanically sealed prior to swelling with fuel.

Clause 36: The method of any of clauses 32-35, further comprisingdepositing or encapsulating an environmental layer over at least aportion of the latex coating layer, wherein the environmental layer isin direct contact with the latex coating layer.

Clause 37: The method of any of clauses 32-35, further comprisingproviding a barrier and/or strengthening layer over at least a portionof the latex coating layer, and depositing or encapsulating anenvironmental layer over at least a portion of the barrier and/orstrengthening layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the application of rigid cut sheets of coating material to thesurface of a fuel tank as is known in the art;

FIG. 2 is an isometric view of a formed container of a fuel tankaccording to one aspect of the present invention;

FIG. 3 is a diagram depicting the application of a coating compositionaccording to another aspect of the present invention;

FIG. 4 is a diagram depicting the application of a coating compositionaccording to another aspect of the present invention; and

FIG. 5 is an isometric view of a self-sealing fuel tank according toanother aspect of the present invention.

DETAILED DESCRIPTION

It is to be understood that at least some of the figures anddescriptions of the invention have been simplified to illustrateelements that are relevant for a clear understanding of the invention,while eliminating, for purposes of clarity, other elements that those ofordinary skill in the art will appreciate may also comprise a portion ofthe invention. However, because such elements are well known in the art,and because they do not facilitate a better understanding of theinvention, a description of such elements is not provided herein.

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols and reference characters typically identify similarcomponents throughout several views, unless context dictates otherwise.The illustrative embodiments described in the detailed description,drawings and claims are not meant to be limiting. Other embodiments maybe utilized, and other changes may be made, without departing from thescope of the technology described herein.

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

It is further understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. The followingdescribed teachings, expressions, embodiments, examples, etc. shouldtherefore not be viewed in isolation relative to each other. Varioussuitable ways in which the teachings herein may be combined will bereadily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

Before explaining the various embodiments of the fuel tank in detail, itshould be noted that the various embodiments disclosed herein are notlimited in their application or use to the details of construction andarrangement of parts illustrated in the accompanying drawings anddescription. Rather, the disclosed embodiments may be positioned orincorporated in other embodiments, variations and modifications thereof,and may be practiced or carried out in various ways. Accordingly,embodiments of the fuel tanks disclosed herein are illustrative innature and are not meant to limit the scope or application thereof.Furthermore, unless otherwise indicated, the terms and expressionsemployed herein have been chosen for the purpose of describing theembodiments for the convenience of the reader and are not meant to limitthe scope thereof. In addition, it should be understood that any one ormore of the disclosed embodiments, expressions of embodiments, and/orexamples thereof, can be combined with any one or more of the otherdisclosed embodiments, expressions of embodiments, and/or examplesthereof, without limitation.

Also, in the following description, it is to be understood that termssuch as outward, inward, above and the like are words of convenience andare not to be construed as limiting terms. Terminology used herein isnot meant to be limiting insofar as devices described herein, orportions thereof, may be attached or utilized in other orientations. Thevarious embodiments will be described in more detail with reference tothe drawings.

The discussion of the invention may describe certain features as being“particularly” or “preferably” within certain limitations (e.g.,“preferably”, “more preferably”, or “most preferably”, within certainlimitations). It is to be understood that the invention is not limitedto these particular or preferred limitations but encompasses the entirescope of the disclosure.

Additionally, as used herein, a second layer and/or second compositiondeposited and/or provided “over” a first layer and/or first compositionmeans that the second layer and/or second composition is further awayfrom the substrate (e.g., internal and/or external surfaces) than thefirst layer and/or first composition, but does not necessarily mean thatthe second layer and/or second composition is in direct contact with thefirst layer and/or first composition and does not prohibit additionallayers and/or compositions from being positioned therebetween, nor doesthe term “over” prohibit the second layer and/or second composition frombeing in direct contact with the first layer and/or first composition.

While several aspects of the fuel tank are shown in the accompanyingfigures and described in detail hereinabove, other aspects will beapparent to, and readily made by, those skilled in the art withoutdeparting from the scope and spirit of the disclosure. Accordingly, theforegoing description is intended to be illustrative rather thanrestrictive. The invention described hereinabove is defined by theappended claims and all changes to the invention that fall within themeaning and range of equivalency of the claims are to be embraced withintheir scope.

In one non-limiting example of the present invention, a method offorming a self-sealing fuel tank is provided. Referring to FIG. 2, themethod of forming a self-sealing fuel tank includes providing acontainer 1. The container 1 comprises external surfaces 3 and internalsurfaces 4 (see FIG. 4). The container 1 may comprise any material knownin the art.

For example, the container 1 may comprise metallic materials and/ornon-metallic materials. The container 1 may comprise a metallic materialincluding, but not limited to, steel, cold-rolled steel, galvanizedsteel, stainless steel, tin, aluminum, zinc, iron, and a combinationthereof. The container 1 may comprise a non-metallic material including,but not limited to, polymers and plastics such as a polyolefin,polyethylene such as high molecular weight polyethylene (HDPE), lowmolecular weight polyethylene (LDPE), crosslinked polyethylene (XLPE),and/or ultra-high molecular weight polyethylene (UHMWPE), polyester,polyamide, polyimide, poly(meth)acrylate, polypropylene, nylons,polyether ether ketone, and combinations thereof, and composites such asfiberglass, carbon fiber and epoxy blends, epoxy infusions with variousfillers, polyimides and carbon fiber composites, and combinationsthereof. The container 1 may comprise rubber, including, but not limitedto, natural rubber, synthetic rubber such as chloroprene rubber,styrene-butadiene rubber, nitrile rubber, and/or the like, or acombination thereof.

The container 1 may also include an opening 5. The opening 5 may allowfor a fuel to be added to the container 1 and contained within theinternal surfaces 4. The opening 5 may be connected to one or more pipesand/or tubes and one or more valves that allow for the opening to beopen or closed, such that, when the container 1 is not being filled, theopening 5 may be closed from external contaminates.

The container 1 comprises an internal volume that is configured tocontain a fuel. The fuel may include gasoline, diesel fuel, motor oil,other petroleum-based compounds, and the like.

The method further includes forming a latex coating layer 9 over atleast a portion of the internal surfaces 4 and/or external surfaces 3 ofthe container 1.

In some non-limiting embodiments, the latex coating layer 9 may beformed by molding and curing a latex coating composition 6 (describedbelow) into preformed layers. The preformed layers of latex coatingcomposition 6 may be formed such that the preformed layers correspond tothe shape of the internal surfaces 4 and/or external surfaces 3 of thecontainer 1. The preformed layers may then be affixed to at least aportion of the internal surfaces 4 and/or external surfaces 3 of thecontainer 1.

Referring to FIG. 3, in some non-limiting embodiments, the latex coatinglayer 9 may be formed by applying a latex coating composition 6 onto atleast a portion of the internal surfaces 4 and/or external surfaces 3 ofthe container 1. For example, the applying step may include spraying,casting, brushing, rolling, dipping, and/or similar methods of applyinga coating composition. The spraying, casting, dipping, brushing,rolling, and/or the like of the latex coating composition 6 has thebenefit of significantly reducing the amount of time to produce aself-sealing fuel tank by up to 30% based on the amount of time toproduce a self-sealing fuel tank using known methods in the art (i.e.,FIG. 1). For example, the applying step may include spraying the latexcoating composition 6 onto at least a portion of the internal surfaces 4and/or external surfaces 3 of the container 1. The latex coatingcomposition 6 may be selected such that it may be sprayed from areservoir by a spraying gun 7. The spray gun 7 may shoot a stream 8 ofthe latex coating composition 6 in the direction of the container 1,such that the latex coating composition 6 may be deposited onto at leasta portion of the external surfaces 3 and/or the internal surfaces 4 ofthe container 1. Additionally, the sprayability of the latex coatingcomposition 6 also allows for the swellable latex coating layer 9 to beformed over complex geometries. In the prior art, it is difficult to cutand shape enough sheets of swellable material to cover the entiresurface of the fuel tank leading to increased production times and poorcoating coverage.

The spraying gun 7 may apply the latex coating composition 6 to theexternal surfaces 3 of the container 1. If the latex coating composition6 is to be applied to the external surfaces 3, the container 1 may befully formed into the desired geometry prior to spraying the latexcoating composition 6 onto the external surfaces 3. Alternatively, thelatex coating composition 6 may be applied to the external surfaces ofthe container 1 prior to forming the final geometry of the container 1,such as applying the latex coating composition 6 to individual containersurface sheets that will be fastened together to form the container 1 orapplying the latex coating composition 6 to the external surfaces 3 ofthe unfolded container 1, where each unfolded side will be folded alonga specified line and fastened to adjacent surfaces to form the container1. Alternatively or in addition to applying the latex coatingcomposition 6 to the external surfaces 3 of the container 1, the spraygun 7 may apply the latex coating composition 6 to the internal surfaces4 of the container 1, as is shown in FIG. 4. If the latex coatingcomposition 6 is to be applied to the internal surfaces 4, the latexcoating composition 6 may be applied to the internal surfaces 4 of thecontainer 1 prior to forming the final geometry of the container 1. Assuch, the container 1 may be partially formed, such that the spray gun 7may apply the latex coating composition 6 to the internal surfaces 4 ofthe container 1.

The latex coating composition 6 includes at least one latex polymer. Asused herein, a “latex polymer” refers to polymeric particles that havebeen dispersed in an aqueous medium to form an emulsion. The at leastone latex polymer may be any rubber or elastomer known in the art. Forexample, the latex coating composition 6 may include at least one latexpolymer that forms a coating that swells when contacted with a fuel. Theat least one latex polymer may be a swellable latex polymer that swellsor initiates the swelling of the latex coating composition it iscontained within. The at least one latex polymer may comprise a naturallatex polymer, a synthetic latex polymer, or a combination thereof. Asused herein, a “natural” latex polymer refers to a latex polymer that isderived from natural resources and needs no additional chemicalsynthesis. As used herein, a “synthetic” latex polymer refers to a latexpolymer that is produced from chemical synthesis. If the latex coatingcomposition 6 comprises a synthetic latex polymer, the synthetic latexpolymer may provide the latex coating composition 6 with reduced fungalgrowth and reduced allergic reaction potential. Non-limiting examples ofa synthetic latex polymer include chloroprene rubber, styrene-butadienerubber, nitrile rubber, and/or the like.

The latex coating composition 6 may include at least one latex polymer,or at least two latex polymers, or at least three latex polymers, or atleast four latex polymers. For example, the latex coating composition 6may include at least two latex polymers comprising at least a firstlatex polymer and second latex polymer. In some non-limitingembodiments, the latex coating composition 6 may comprise at least twolatex polymers, where the first latex polymer is a swellable latexpolymer and the second latex polymer is not a swellable latex polymer.In some non-limiting embodiments, the latex coating composition 6comprises at least two latex polymers, wherein both the first and secondlatex polymers are swellable latex polymers. In some non-limitingembodiments, if more than one latex polymer is present in the latexcoating composition 6, one of said latex polymers may be a swellablelatex polymer while the remaining latex polymers are optionallyswellable latex polymers.

The latex coating composition 6 may comprise the at least one latexpolymer in at least 40 weight %, or at least 45 weight %, or at least 50weight %, based on the total solids weight of the latex coatingcomposition. The latex coating composition 6 may comprise the at leastone latex polymer in up to 70 weight %, based on the total solids weightof the latex coating composition. The latex coating composition 6 maycomprise the at least one latex polymer in the range of from 40 weight %to 70 weight %, or in the range of from 45 weight % to 70 weight %, orin the range of from 50 weight % to 70 weight %, based on the totalsolids weight of the latex coating composition.

The latex coating composition 6 may include a curing agent. As usedherein, a “curing agent” refers to a compound that reacts with thefunctionality of one or more compounds present to form crosslinksbetween said one or more compounds in order to cure the latex coatingcomposition. The curing agent may be any curing agent known in the artto cure latex-based coating compositions. For example, the curing agentmay comprise a transition metal. Non-limiting examples of curing agentsinclude zinc-containing curing agents such aszinc-2-mercaptobenzothia-zole, zinc dithiocarbamates, and combinationsthereof.

The at least one latex polymer may be provided in combination with thecuring agent in the form of a latex base mixture. The latex base mixturemay further include additional components, such as additives includingcolorants, antioxidants, and/or the like. The latex coating composition6 may comprise the latex base mixture (e.g., at least one latex polymer,curing agent, and optional additives) in the range of from 40 weight %to 70 weight %, based on the total solids weight of the latex coatingcomposition.

The latex coating composition 6 may include a foaming agent. As usedherein, a “foaming agent” refers to any compound that facilitates theformation of foam. The foaming agent may increase the surface area ofthe portion of the latex coating layer 9 that swells while alsoincreasing the swelling rate and decreasing the density of the latexcoating layer 9. The latex coating composition 6 may include any foamingagent known in the art. For example, the foaming agent may includesurfactants, blowing agents, or combinations thereof.

The latex coating composition 6 may include any surfactant known in theart. Non-limiting examples of surfactants include sulfates, sulfonates,phosphates, carboxylates, ethoxylates, fatty acid esters, potassiumhydroxide, and/or the like.

The latex coating composition 6 may include any blowing agent known inthe art. Non-limiting examples of blowing agents includechlorofluorocarbons, hydrochlorofluorocarbons, hydrocarbons, liquidcarbon dioxide, isocyanates, azodicarbonamide, hydrazine and likenitrogen-based compounds, sodium bicarbonate, and/or the like.

The foaming agent may be provided in solution, such as a foaming agentin solvent and/or water.

The latex coating composition 6 may comprise the foaming agent in atleast greater than 0 weight %, or at least 1 weight %, based on thetotal weight of the latex coating composition. The latex coatingcomposition 6 may comprise the foaming agent in up to 30 weight %, or upto 20 weight %, or up to 16 weight %, based on the total weight of thelatex coating composition. The latex coating composition 6 may comprisethe foaming agent in the range of from greater than 0 weight % to 30weight %, or in the range of from greater than 0 weight % to 20 weight%, or in the range of from greater than 0 weight % to 16 weight %, or inthe range of from 1 weight % to 20 weight %, or in the range of from 1weight % to 16 weight %, based on the total weight of the latex coatingcomposition.

The latex coating composition 6 may include a gelling agent, such as anionic gelling agent. As used herein, a “gelling agent” refers to acompound that can form a gel and increases the viscosity of the latexcoating composition without changing the other properties of the coatingcomposition. The latex coating composition 6 may include any gellingagent known in the art that may gel the present coating compositions.For example, the gelling agent may comprise sodium silicofluoride,and/or the like.

The gelling agent may be provided in solution, such as a gelling agentin solvent and/or water.

The latex coating composition 6 may comprise the gelling agent in atleast greater than 0 weight %, or at least 0.3 weight %, based on thetotal weight of the latex coating composition. The latex coatingcomposition 6 may comprise the gelling agent in up to 10 weight %, or upto 4 weight %, based on the total weight of the latex coatingcomposition. The latex coating composition 6 may comprise the gellingagent in the range of from greater than 0 weight % to 10 weight %, or inthe range of from 0.3 weight % to 4 weight %, based on the total weightof the latex coating composition.

The latex coating composition 6 may comprise a thickening agent. Athickening agent, also known as a rheological modifier, may be used tomodify the viscosity of the latex coating composition 6. For example,the latex coating composition 6 may comprise a non-ionic associativethickener. As used herein, “associative” thickeners refer to thickenerswhich comprise a mechanism by which they thicken which is believed toinvolve hydrophobic associations between the hydrophobic moieties in thethickener molecules and/or between the hydrophobic moieties in thethickener molecules and other hydrophobic surfaces. A “non-ionic”associative thickener refers to a thickener molecule with no charge andthat does not dissociate into ions when in solution. The non-ionicnature of the non-ionic associative thickener maintains the foam andcolloidal stability while increasing its viscosity, which is contrary toionic rheological modifiers. Non-ionic associative thickeners include,but are not limited to, HEAT type (mealamine/aminoplast linkages), HEURtype (urethane linkages), associative thickeners with polymericbackbones constructed from one or more blocks of polymerized oxyalkyleneunits (e.g., polyethylene oxide, polypropylene oxide, and/or the like)with hydrophobic groups attached to or within the backbone, associativethickeners with a cellulosic backbone with hydrophobic groups attachedto the backbone, non-ionic polyether thickeners, polyether associativethickeners, and/or the like.

Alternatively, the latex coating composition 6 may be substantiallyfree, essentially free, or completely free of a thickening agent. Thephrase “substantially free of a thickening agent” means that the latexcoating composition 6 contains less than 1000 parts per million byweight (ppm) of a thickening agent based on the total solids weight ofthe latex coating composition 6, “essentially free of a thickeningagent” means that the latex coating composition 6 contains less than 100ppm of a thickening agent based on the total solids weight of the latexcoating composition 6, and “completely free of a thickening agent” meansthat the latex coating composition 6 contains less than 20 parts perbillion by weight (ppb) of a thickening agent based on the total solidsweight of the latex coating composition 6. For example, the latexcoating composition 6 may comprise no thickening agent.

Alternatively, the latex coating composition 6 may be substantiallyfree, essentially free, or completely free of a non-ionic associativethickener. The phrase “substantially free of a non-ionic associativethickener” means that the coating latex composition 6 contains less than1000 ppm of a non-ionic associative thickener based on the total solidsweight of the latex coating composition 6, “essentially free of anon-ionic associative thickener” means that the latex coatingcomposition 6 contains less than 100 ppm of a non-ionic associativethickener based on the total solids weight of the latex coatingcomposition 6, and “completely free of a non-ionic associativethickener” means that latex coating composition 6 contains less than 20ppb of a non-ionic associative thickener based on the total solidsweight of the latex coating composition 6. For example, the latexcoating composition 6 may comprise no non-ionic associative thickener.

The latex coating composition 6 may include a colorant. As used herein,a “colorant” refers to a compound that imparts color or opacity changeand/or effect to the latex coating composition. The colorant may be inthe form of solid particles and/or flakes, or provided in a dispersionor solution. Examples of colorants include pigments, dyes, tints, andthe like. For example, in one non-limiting embodiment, the latex coatingcomposition 6 may comprise a tint, such as a MIXOL brand, binder-freetint under the name multi-purpose tinting paste, universal tintingbaste, universal tint, and the like.

Example pigments include carbazole dioxazine crude pigment, azo,monoazo, diazo, naphthol AS, benzimidazolone, isoindolinone, isoindolineand polycyclic phthalocyanine, quinacridone, perylene, perinone,diketopyrrolo pyrrole, thioindigo, anthraquinone, indanthrone,anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone, dioxazine,triarylcarbonium, quinophthalone pigments, diketo pyrrolo pyrrole red(“DPPBO red”), titanium dioxide, carbon black, and mixtures thereof.

Example dyes include phthalo green or blue, iron oxide, bismuthvanadate, anthraquinone, and perylene and quinacridone.

For example, the latex coating composition 6 may include a colorantcomprising a pigment, such as a black pigment. The black pigment may beused in the latex coating composition 6, such that the latex coatinglayer 9 comprises a black or a dark grey aesthetic.

The latex coating composition 6 may comprise the colorant typically inthe range of from 0.5 weight % to 1 weight %, based on the total solidsweight of the latex coating composition.

The latex coating composition 6 may be a one-component (1K) coatingcomposition. As used herein, a “one-component (1K)” coating compositionrefers to a composition where all of the components are maintained inthe same container during storage, and may remain stable for longer than24 hours at ambient conditions. For example, the latex coatingcomposition 6 may be a one-component (1K) coating composition that isstable at ambient conditions for longer than 10 minutes, or for longerthan 20 minutes, or for longer than 30 minutes, or for longer than 1hour, or for longer than 2 hours, or for longer than 5 hours, or forlonger than 10 hours, or for longer than 24 hours, or for longer than 48hours, or for longer than 1 week, or for longer than 1 month, or forlonger than 1 year.

Alternatively, the latex coating composition 6 may be a two-component(2K) coating composition. As used herein, a “two-component (2K)” coatingcomposition refers to a composition where at least two components aremaintained in separate containers during storage prior to application toa substrate.

The materials used to form the latex coating composition 6 as describedherein not only produce coatings with swellable and septum properties,but also reduce the cost of forming the latex coating composition 6. Forexample, the specific materials chosen for the latex coating composition6, in combination with the ability to apply the latex coatingcomposition 6 using a method other than cutting individual sheets ofmaterial, results in a reduction in the cost of form the swellable latexcoating layer and the self-sealing fuel tank compared to a swellablelatex coating layer formed by known materials and forming individualsheets of material to form the self-sealing fuel tank.

The latex coating composition 6 may be formed by first measuring outappropriate amounts, such as the amounts described herein, of at leastone latex polymer, curing agent, pigment, optional antioxidants, and/orfoaming agent, and adding each of said components to a mixer and mixingfor a period of time, such as mixing for 2 minutes to 7 minutes. Aftermixing the aforementioned components, a gelling agent may be measured inthe appropriate amount, such as the amounts described herein, and addedto the mixer. The mixture with gelling agent may then be mixed until adesired volume is achieved, thereby forming the latex coatingcomposition 6. For example, this process of forming the latex coatingcomposition 6 may form a one-component latex coating composition.

After formation of the latex coating composition 6, the latex coatingcomposition 6 may be loaded into a spray gun 7, such as a single-partsprayer. The phrase “single-part” sprayer means that the sprayer onlyloads one component or composition, instead of twocomponents/compositions that are mixed together during spraying. Thelatex coating composition 6 is then sprayed by the spray gun 7 onto theexternal surfaces 3 and/or internal surfaces 4 of the container 1. Thespray gun 7 may spray the latex coating composition 6 with a pressure ofabout 1 atm (i.e., 13-15 psi).

The forming of the latex coating layer 9 may further include curing thelatex coating composition 6. The latex coating composition 6 may becured after the latex coating composition 6 has been applied to theexternal surfaces 3 and/or the internal surfaces 4 of the container 1.Alternatively, the latex coating composition 6 may be cured in a mold toform preformed layers. The latex coating composition 6 may be cured atambient conditions. As used herein, “ambient conditions” refers to atemperature in the range of from 20° C.-25° C. and a pressure of about 1atm. For example, the latex coating composition 6 may be cured atambient conditions for greater than 8 hours, or greater than 12 hours,or greater than 24 hours, or greater than 48 hours.

Alternatively, the latex coating composition 6 may be cured at elevatedconditions. For example, the latex coating composition 6 may typicallybe cured at a temperature of greater than 50° C., or greater than 60°C., or greater than 70° C. The latex coating composition 6 may typicallybe cured at a temperature of up to 95° C., or up to 90° C., or up to 80°C. The latex coating composition 6 may be cured at a temperature in therange of 50° C. to 95° C., or in the range of 60° C. to 95° C., or inthe range of 60° C. to 90° C., or in the range of 70° C. to 80° C. Thelatex coating composition 6 may be cured at elevated conditions forgreater than 2 hours, or greater than 3 hours, or greater than 4 hours.The latex coating composition 6 may be cured at elevated conditions forup to 24 hours, or up to 20 hours, or up to 18 hours. The latex coatingcomposition 6 may be cured at elevated conditions for 2 hours to 24hours, or for 2 hours to 20 hours, or for 2 hours to 18 hours, or for 3hours to 24 hours, or for 3 hours to 20 hours, or for 3 hours to 18hours, or for 4 hours to 24 hours, or for 4 hours to 20 hours, or for 4hours to 18 hours.

Once the final latex coating composition 6 is cured, a latex coatinglayer 9 is formed. The latex coating layer 9 is a swellable latexcoating layer 9. As used herein, a “swellable” latex coating layerrefers to a coating layer that expands beyond its final cured dimensionswhen contacted with a fuel. For example, the fuel that contacts theswellable latex coating layer 9 may be a fuel comprising gasoline and/ordiesel fuel. The swellable latex coating layer 9 may be in directcontact with the external surfaces 3 and/or the internal surfaces 4 ofthe container 1.

For example, in the field of vehicles and machinery, fuel tanks may bepunctured, allowing for fuel contained within the fuel tank to leak out.By coating the fuel tank with a swellable latex coating layer 9, theswellable latex coating layer 9 will swell when contacted with the fuelvia the leakage through the punctured hole in the container 1. Thecontacting of the fuel with the latex coating layer 9 initiates theswelling of the latex coating layer 9. For example, the contacting ofthe fuel with the latex coating layer 9 may reduce the modulus of thelatex coating layer 9, thus allowing the latex coating layer 9 to expandinward to seal the one or more punctures. Once the one or more puncturesare sealed, the fuel can no longer contact the latex coating layer 9 andtherefore no long swells and/or expands.

In addition to the swelling properties, the swellable latex coatinglayer 9 also comprises septum properties. For example, if the fuel tankis punctured, including puncturing the swellable latex coating layer 9,the elastomeric properties of the swellable latex coating layer 9 willcause the swellable latex coating layer 9 surrounding the puncture toinstantaneously and elastically return to its original form, therebypartially, or even completely, sealing the puncture hole prior to thelatex coating layer 9 swelling due to contact with the fuel, such thatno additional fuel may exit via said recently sealed hole. The swellablelatex coating layer 9 may have an elongation strain that is sufficientto maintain the structural integrity of the swellable latex coatinglayer 9 when the tank rapidly expands from ballistic pressure. As such,the swellable latex coating layer 9 discussed herein has the benefit ofreducing the cost and the time needed to form a fuel tank with no lossin the ballistic functionality. The swellable latex coating layer 9 mayhave a density that allows for additional materials, such as theenvironmental layer 10, to be added over at least a portion of theswellable latex coating layer 9 without sacrificing the structuralintegrity of the swellable latex coating layer 9. As used herein,maintaining the “structural integrity” of the swellable latex coatinglayer 9 refers to the ability of the swellable latex coating layer 9 toremain a continuous coating deposited onto the external surfaces 3and/or internal surfaces 4 of the container 1 when placed under one ormore stresses. The swellable latex coating layer 9 may be of sufficientthickness to allow for the septum properties and swelling properties mayeffectively seal the one or more holes.

The swellable latex coating layer 9 may have a density of at least 0.09grams per cubic centimeter (g/cc). The swellable latex coating layer 9may have a density of up to 0.50 g/cc. The swellable latex coating layer9 may have a density in the range of from 0.09 g/cc to 0.50 g/cc. Theswellable latex coating layer 9 may achieve a density in the range offrom 0.09 g/cc to 0.50 g/cc without the inclusion of a thickening agent,such as a non-ionic associative thickener. Unless stated otherwise,density was calculated herein by measuring the mass and the dimensionsof a die-cut cured specimen of material, where the dimensions weremeasured using SPI digital calipers, model 15-719-8, and mass wasmeasured using a Sartorius digital balance, model ENTRIS3202-1S.

The swellable latex coating layer 9 may have a tensile strength of atleast 20 psi. The swellable latex coating layer 9 may have a tensilestrength of up to 200 psi. The swellable latex coating layer 9 may havea tensile strength in the range of from 20 psi to 200 psi. The swellablelatex coating layer 9 may achieve a tensile strength in the range offrom 20 psi to 200 psi without the inclusion of a thickening agent, suchas a non-ionic associative thickener. Unless stated otherwise, tensilestrength was measured herein in accordance with ASTM D412-A using aShimadzu Load Frame, model AGS-X, and a 1 kN load cell.

The method may optionally include applying additional coatingcompositions over at least a portion of the latex coating layer 9, andcuring the additional coating compositions to form additional coatinglayers over at least a portion of the latex coating layer 9. Theadditional coating compositions may comprise any of the components ofthe latex coating composition 6. The additional coating compositions maybe cured to form swellable coating layers. For example, additionalcoating compositions may be applied over at least a portion of theswellable latex coating layer 9 to form at least one additional coatinglayer, or at least two additional coating layers, or at least threeadditional coating layers, or at least four additional coating layers.

The method may optionally include providing a barrier and/orstrengthening layer (not shown) over at least a portion of the swellablelatex coating layer 9. The barrier and/or strengthening layer mayprovide additional support to the swellable latex coating layer 9 inmaintaining its application onto the container 1 and its structuralintegrity. Non-limiting examples of materials that may be used for thebarrier and/or strengthening layer include Kevlar (commerciallyavailable from DuPont de Nemours, Inc.) and Dyneema (commerciallyavailable from Koninklijke DSM N.V.). Alternatively, the latex coatingcomposition 6 that forms the swellable latex coating layer 9 may besufficient in achieving the desired application and structuralintegrity, such that no barrier and/or strengthening layers are presentover the swellable latex coating layer 9.

Referring to FIG. 5, the method further includes depositing and/orencapsulating an environmental layer 10 over at least a portion of thelatex coating layer 9 (or barrier and/or strengthening layer, ifpresent). The environmental layer 10 may be deposited over at least aportion of the external surfaces 3 and/or the internal surfaces 4,depending on which surfaces the swellable latex coating layer 9 wasdeposited over. The environmental layer 10 may encapsulate at least aportion of the latex coating layer 9 by forming preformed layers thatare cut to the shape of the container 1 and affixed to at least aportion of the latex coating layer 9 (or barrier and/or strengtheninglayer, if present). The environmental layer 10 may be used to protectthe surrounding environment from exposure to the underlying coatinglayers.

The environmental layer 10 may be deposited using any technique known inthe art. For example, the environmental layer 10 may be applied in theform of an environmental coating composition and subsequently cured toform the environmental layer 10. The environmental coating compositionmay be sprayed, casted, and/or affixed as preformed layers over thelatex coating layer 9. The environmental coating composition may becured to form the environmental layer 10 at ambient conditions forgreater than 1 hour, or greater than 2 hours, or greater than 4 hours,or for greater than 8 hours, or greater than 12 hours. Alternatively,the environmental coating composition may be cured at elevatedconditions.

The environmental coating composition may comprise a preformed polymershape. For example, the environmental coating composition may comprise athermoplastic polymer, a thermoset polymer, or a combination thereof. Asused herein, a “thermoplastic” polymer is a polymer that softens whenheated and may be reformed. As used herein, a “thermoset” polymer is apolymer that is irreversibly hardened by curing that prevents saidpolymer from softening and being reshaped. The environmental coatingcomposition may comprise a polymer such as a polyurethane, an epoxyresin, a polyolefin such as polyethylene, polypropylene, and the like, a(meth)acrylate polymer, or a combination thereof. The environmentalcoating composition may include additional components, such as pigments,gelling agents, foaming agents, and combinations thereof. In onenon-limiting embodiment, the environmental coating composition comprisesa polyurethane polymer. In another non-limiting embodiment, theenvironmental coating composition comprises polyethylene.

The environmental coating composition may be deposited directly over atleast a portion of the swellable latex coating layer 9, such that theenvironmental layer 10 is in direct contact with the swellable latexcoating layer 9. In addition to serving as a protective layer for theswellable latex coating layer 9, the environmental layer 10 providesincreased sealing function in concert with the swellable latex coatinglayer 9 and mechanical stability in operation. When applied to theswellable latex coating layer 9, the environmental coating compositionmechanically bonds to the swellable latex coating layer 9. When thecontainer 1 is punctured, the environmental layer 10 adjacent to thepunctured area may experience some degree of elastic deformation.Coupling the aforementioned expected elastic deformation of theenvironmental layer 10 with the mechanical bonding of the environmentallayer 10 and the swellable latex coating layer 9 may promote increasedseptum properties of the environmental layer 10 and the swellable latexcoating layer 9, resulting in additional hole-closure at the puncturearea. As such, providing the environmental layer 10 in direct contactwith the swellable latex coating layer 9 may provide an unexpectedincrease in septum properties that aids in closure of a puncture.

Additionally, the mechanical bonding of the environmental layer 10 tothe swellable latex coating layer 9 aids in maintaining the position ofthe swellable material of the swellable latex coating layer 9 in thedirection parallel to the external surfaces 3 and/or internal surfaces 4of the container 1. During curing, the environmental layer 10 mayslightly shrink to create a compression between the swellable latexcoating layer 9 and the external surfaces 3 and/or internal surfaces 4of the container 1. Due in part to the elastic modulus of theenvironmental layer 10, which is expected to be higher than that of theswellable material of the swellable latex coating layer 9, excessiveswelling of the swellable latex coating layer 9 in a directionperpendicular to the external surfaces 3 and/or internal surfaces 4 ofthe container 1 is minimized, thereby allowing the swellable latexcoating layer 9 to follow the path of least resistance during swelling(i.e., towards the puncture hole).

The method may optionally include depositing an adhesion promoter 11over at least a portion of the external surfaces 3 and/or internalsurfaces 4 of the container 1 prior to forming the latex coating layer9. The adhesion promotor 11 may increase the adhesion of the latexcoating composition 6 and resultant swellable latex coating layer 9 tothe external surfaces 3 and/or internal surfaces 4 of the container 1.The adhesion promoter may include any adhesion promoter known in theart. Non-limiting examples of adhesion promoters include organosilanes,organotitanates, organozirconates, chlorinated polyolefins, siliconemodified polyolefins, acrylic acid modified polyolefins, maleicanhydride modified polyolefins, metallic diacrylate, fatty esters,melamine cyanurate, and the like.

The latex coating layer 9 may be formed to repair a fuel tank. Forexample, a fuel tank that comprises one or more punctures may have thelatex coating layer 9 formed over at least a portion of the internalsurfaces 4 and/or external surfaces 3 of the container 1 to swell andseal said punctures when contacted with the fuel or seals said puncturesvia the septum properties of the latex coating layer 9.

Although various embodiments have been described herein, manymodifications, variations, substitutions, changes, and equivalents tothose embodiments may be implemented and will occur to those skilled inthe art. It is therefore understood that the foregoing description andthe appended claims are intended to cover all such modifications andvariations as falling within the scope of the disclosed embodiments. Thefollowing claims are intended to cover all such modifications andvariations.

What is claimed is:
 1. A method of forming a self-sealing fuel tank,comprising: providing a container comprising internal surfaces andexternal surfaces and configured to hold a fuel; forming a latex coatinglayer over at least a portion of the internal surfaces and/or externalsurfaces; depositing or encapsulating an environmental layer over atleast a portion of the latex coating layer; wherein the latex coatinglayer swells when contacted with the fuel; and wherein the latex coatinglayer is formed from a latex coating composition that is substantiallyfree of a non-ionic associative thickener.
 2. The method of claim 1,wherein the forming step further comprises applying the latex coatingcomposition onto at least a portion of the internal surfaces and/or theexternal surfaces, and curing the latex coating composition to form thelatex coating layer.
 3. The method of claim 1, wherein the forming stepfurther comprises molding and curing the latex coating composition intopreformed layers, and affixing the preformed layers over at least aportion of the internal surfaces and/or external surfaces.
 4. The methodof claim 1, further comprising depositing an adhesion promoter over atleast a portion of the internal surfaces and/or external surfaces priorto forming the latex coating layer.
 5. The method of claim 2, whereinthe applying step comprises spraying, casting, rolling, brushing, and/ordipping the latex coating composition onto at least a portion of theexternal surfaces of the container.
 6. The method of claim 2, whereinthe applying step comprises spraying, casting, rolling, brushing, and/ordipping the latex coating composition onto at least a portion of theinternal surfaces of the container.
 7. The method of claim 1, whereinthe depositing or encapsulating step further comprises spraying and/orcasting an environmental coating composition over at least a portion ofthe latex coating layer and curing the environmental coating compositionto form the environmental layer, or molding and curing the environmentalcoating composition into preformed layers and affixing the preformedlayers over at least a portion of the latex coating layer.
 8. The methodof claim 1, further comprising compounding at least one latex polymer,an ionic gelling agent, and a foaming agent, to form the latex coatingcomposition.
 9. The method of claim 2, wherein the curing step comprisesheating the latex coating composition to a temperature in the range of60° C. to 95° C.
 10. The method of claim 1, wherein the latex coatingcomposition is a one-component coating composition.
 11. The method ofclaim 1, further comprising providing a barrier and/or strengtheninglayer over at least a portion of the latex coating layer, and depositingor encapsulating the environmental layer over at least a portion of thebarrier and/or strengthening layer.
 12. A self-sealing fuel tank,comprising: a container comprising internal surfaces and externalsurfaces and configured to hold a fuel; a latex coating layer over atleast a portion of the internal surfaces and/or external surfaces; andan environmental layer over at least a portion of the latex coatinglayer; wherein the latex coating layer swells when contacted with thefuel; and wherein the latex coating layer is formed from a latex coatingcomposition that is substantially free of a non-ionic associativethickener.
 13. The self-sealing fuel tank of claim 12, furthercomprising an adhesion promoter over at least a portion of the internalsurfaces and/or external surfaces and in between the portion of theinternal surfaces and/or external surfaces and the latex coating layer.14. The self-sealing fuel tank of claim 12, wherein the latex coatinglayer is over at least a portion of the internal surfaces.
 15. Theself-sealing fuel tank of claim 12, wherein the latex coating layer isover at least a portion of the external surfaces.
 16. The self-sealingfuel tank of claim 12, wherein the container comprises a metal, aplastic, and/or a rubber.
 17. The self-sealing fuel tank of claim 12,wherein the latex coating composition comprises at least one latexpolymer.
 18. The self-sealing fuel tank of claim 17, wherein the latexcoating composition further comprises an ionic gelling agent.
 19. Theself-sealing fuel tank of claim 17, wherein the latex coatingcomposition further comprises a foaming agent.
 20. The self-sealing fueltank of claim 17, wherein the latex coating composition furthercomprises a colorant.
 21. The self-sealing fuel tank of claim 17,wherein the latex coating composition further comprises a thickeningagent.
 22. The self-sealing fuel tank of claim 12, wherein the latexcoating composition is sprayed, casted, rolled, brushed and/or dippedonto at least a portion of the internal surfaces and/or the externalsurfaces.
 23. The self-sealing fuel tank of claim 12, wherein the latexcoating composition is molded and cured into preformed layers, and thepreformed layers are affixed to at least a portion of the internalsurfaces and/or external surfaces.
 24. The self-sealing fuel tank ofclaim 12, wherein the latex coating composition is a one-componentcoating composition.
 25. A method of sealing one or more punctures inthe wall of a container, comprising: forming a latex coating layer overat least a portion of the internal surfaces and/or external surfaces;wherein the container comprises a fuel which contacts the latex coatinglayer at one or more surfaces exposed by the one or more punctures;wherein said contact between the fuel and the latex coating layer causesthe latex coating layer to swell and seal the one or more punctures; andwherein the latex coating layer is formed from a latex coatingcomposition that is substantially free of a non-ionic associativethickener.
 26. The method of claim 25, wherein the forming step furthercomprises applying the latex coating composition onto at least a portionof the internal surfaces and/or external surfaces, and curing the latexcoating composition to form the latex coating layer.
 27. The method ofclaim 25, wherein the forming step further comprises molding and curingthe latex coating composition into preformed layers, and affixing thepreformed layers over at least a portion of the internal surfaces and/orexternal surfaces.
 28. The method of claim 25, wherein the latex coatinglayer comprises septum properties such that at least one of the one ormore punctures is mechanically sealed prior to swelling with fuel.